Studies are being conducted on the pharmacokinetic disposition of various drugs in the elderly following single and multiple oral doses. Attempts are being made at identifying and quantitating changes in eliminative parameters which might result in altered metabolite patterns or accumulation of drugs and/or their metabolites. Such changes might be expected to occur as a result of diminished hepatic or renal function accompanying advancing age and recognition of them is extremely important if physicians are to prescribe drugs in a way that minimizes adverse reactions in elderly populations.